Common routes for the administration of pharmacologically active agents, nutraceuticals, and vitamins are exemplified by a variety of oral dosage forms such as tablets, pills, and capsules. Additionally, a wide range of foodstuffs and oral hygiene products, such as breath fresheners are also orally dispensed. Such dosage forms are generally convenient, stable in storage and transport, and familiar to the user. However, they are not without problems, and these problems are often significant. It is extremely difficult for most people to swallow any of these oral dosage forms without supplemental water. It is frequently inconvenient or messy to have to take supplementary water with oral medicaments. Such difficulties are compounded for those with swallowing difficulties such as, for example, children and the elderly. Certain medical conditions, such as Parkinsons' disease and other neurological states, make it difficult to swallow oral dosage forms, even with supplemental water.
Children and the elderly often experience difficulty in swallowing and ingesting medicines in solid forms such as tablets, pills, and capsules. Pharmaceuticals in forms which permit easy ingestion and whose active components are rapidly released in the oral cavity are desirable in the event of a medical emergency such as an attack of angina pectoris.
Recently, with diversification of personal preferences in food and textures of food within the mouth, the texture of oral dosage forms of pharmaceuticals is an additional complication in oral medicaments.
In conventional soft gelatin capsules, ingredients are encapsulated in a gelatin shell for consumption. Generally, the shell of a soft gelatin capsule comprises gelatin and a plasticizer to control the softness and flexibility of the shell. The shell further includes water and optionally other additives such as flavorants. The shells are typically dried until the water content is decreased to a certain level so as to prevent the capsule from being deformed or becoming undesirably sticky.
Conventional soft gelatin capsules commonly available are often hard and tough because they are designed to dissolve after reaching the intestines so as to release their contents therein. Such capsules are not easily broken by teeth and are not suitable for chewing. In addition, twisting the capsule with the fingers to open the capsule is often a difficult practice, and generally opening the capsule requires a tool such as scissors. One measure to soften a soft gelatin capsule is to increase the plasticizer content and increase the capsule flexibility. However, this often makes a soft gelatin capsule more likely to stick to another soft gelatin capsule or to a container, thereby causing deterioration in storage stability. Increasing plasticizer content is further problematic in high-temperature, high-humidity regions. Soft gelatin capsules with acceptable dosing, stability, and storage and handling characteristics are typical when a relatively high gelatin content and a relatively low plasticizer and end water content is found in the capsules. However, the chewability, texture and mouth feel, and client acceptance of the capsules are found when a lower gelatin content and higher plasticizer and end water contents is used.
Typically, chewable soft gelatin capsules, or chewable softgels, are designed such that the user chews upon the capsule to release the fill into the mouth instead of swallowing the capsule with the fill still encapsulated within the shell. Furthermore, these chewable softgels are intended to be completely or nearly completely dissolved by chewing. Such capsules are distinguished by particular fabrication problems, such as excessive stickiness during encapsulation and sticking of the end product to other capsules during post-encapsulation handling. Further, chewable softgels with high end water content typically have poor storage performance, sticking to one another in packaging and often melting or leaking during storage. In addition to the effects of water content, chewability of capsules can be affected by the bloom strength and the melting points of the gelatin used. In general, gelatins of lower bloom strength and lower melting point have preferable organoleptic qualities.
U.S. Pat. No. 4,935,243 to Borkan, et al. discloses a chewable gelatin capsule composition that comprises less than about 30%, and preferably comprises about 20-26% water, and is directed to the use of a hydrogenated starch hydrolysate, which allowed a lower than expected end water content. U.S. Pat. No. 4,532,126 to Ebert, et al. discloses examples of soft gelatin capsules formed at as high as 37% water content, but specifies that these capsules were then subsequently dried to some undisclosed final end water content, in order to obtain desired chewing characteristics.
U.S. Pat. No. 3,851,051 to Miskel et al. discloses numerous embodiments of a soft gelatin capsule that has an initial capsule shell water content of between 28.3 and 36.6%, but further discloses that the capsules are then dried to be in equilibrium with the internal gel-lattice composition, which has a water content of 15-20%. In U.S. Pat. No. 6,258,380 to Overholt, capsules are fabricated from a wet mass that is initially as much as 30% water by weight, but is then subsequently dried to 6%-8% water.
U.S. patent application Ser. No. 10/456,450 to Makino; accomplished a high degree of hydration using fish gelatin having a low sol-gel transition temperature, that is, a relatively low melting point. However, such formulations can be problematic when stored at high temperatures or high humidity. For example, it is very difficult to formulate a fish gelatin capsule that will be stable at a storage temperature above 35° C. Capsules made with such low melting point gelatins tend to become sticky during storage, and may even burst or melt, releasing their contents. On the other hand, it is known that mammalian gelatins, some of which have melting temperatures above 60° C., tend to be much more stable at higher storage temperatures, but too often have poorer organoleptic qualities.
There is a need for chewable softgel compositions having commercially acceptable properties at the time the capsules are packaged and made available for sale. Additionally, these chewable capsules should exhibit stability under reasonably expected storage times and conditions. Further, these capsules need to exhibit a soft, pleasant chewing texture and low stickiness.